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Equation for the oxidation reaction for KMnO4 solution

  1. Oct 11, 2009 #1
    Ok so the question goes as such: Write the half equation for the oxidation reaction and then the full net ionic equation for KMnO4 solution mixed with dilute HCL. My main problem is what is getting oxidised?
     
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  3. Oct 11, 2009 #2

    Borek

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    Re: Oxidation?

    Chlorides.

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    methods
     
  4. Oct 11, 2009 #3
    Re: Oxidation?

    chlorides are getting oxidised??? how so?
     
  5. Oct 11, 2009 #4

    Borek

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    Re: Oxidation?

    It is just a matter of potentials, permanganate in solutions of pH low enough is a very strong oxidiser.

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  6. Oct 11, 2009 #5
    Re: Oxidation?

    ok so in this case.. the chlorine will have an oxidation state of minus one to begin with and an oxidation state of -2 to end with?
     
  7. Oct 11, 2009 #6

    Borek

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    Re: Oxidation?

    What is oxidation?

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  8. Oct 11, 2009 #7
    Re: Oxidation?

    sorry its a loss of electrons.. so the Cl- must lose and electron to become Cl?
     
  9. Oct 11, 2009 #8
    Re: Oxidation?

    so the oxidation half equation would be Cl- ---> Cl + e ?
     
  10. Oct 11, 2009 #9

    Borek

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  11. Oct 11, 2009 #10
    Re: Oxidation?

    why Cl2 as opposed to Cl? So it oxidises chlorides to chlorine.. why?????
     
  12. Oct 11, 2009 #11
    Re: Oxidation?

    So the oxidation half equation would be:
    2Cl- --> Cl2 + 2e ?
     
  13. Oct 11, 2009 #12

    Borek

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    Re: Oxidation?

    Which gases are diatomic?

    Edit: yes to your oxidation half reaction.

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  14. Oct 11, 2009 #13
    Re: Oxidation?

    But the reduction equation will be: MnO4- + 8H+ + 5e ---> Mn2+ + 4H2O ... when the oxidation and reduction equations are added together the electrons wont cancel..
     
  15. Oct 11, 2009 #14

    Borek

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    Last edited: Oct 11, 2009
  16. Oct 11, 2009 #15
    Re: Oxidation?

    uhh so multiply all the left side by 2 and the right by 5? then 10 electrons on each and they will cancel?
     
  17. Oct 11, 2009 #16
    Re: Oxidation?

    oh no not that easy.. sorry.. i shall read over that link.. thankyou sooo much foir your help so far.. absolute champion!
     
  18. Oct 11, 2009 #17

    Borek

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    Re: Oxidation?

    That will probably do - it may happen that coefficients in the reaction after will be not the smallest ones, but at least reaction would be correctly balanced.

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  19. Oct 11, 2009 #18
    Re: Oxidation?

    Ok so I get..

    2MnO4-(aq) + 16H+(aq) + 10Cl-(aq) ---> 2Mn2+(aq) + 8H2O(l) + 10Cl2(g)

    I've got three more of these to do.. ill be up all night.. argh!
     
  20. Oct 11, 2009 #19

    Borek

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    Re: Oxidation?

    Divide everything by 2.

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  21. Oct 11, 2009 #20
    Re: Oxidation?

    Ok so the next one is KMnO4 and Na2SO3 in the presence of dilute H2SO4.. however what the heck is the oxidation state of Na2SO3?
     
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